In related art, an image forming apparatus has been known which includes a driving source that rotates only in one direction and a gear mechanism capable of switching a rotating direction of an output gear, to which a driving force from the driving source is transmitted, between one direction and an other direction opposite to the one direction. The gear mechanism is provided with a pendulum gear capable of transmitting the driving to the output gear. In this configuration, it is possible to change a transmission path to the output gear by swinging the pendulum gear. Thereby, it is possible to change a rotating direction of the output gear.
However, in the related-art image forming apparatus, since it is necessary to secure a space in an apparatus main body, in which the pendulum gear can swing, it is not possible to achieve space-saving the image forming apparatus.